The Narwhal (meaning "corpse whale" in Old Norse) is a rarely seen Arctic whale. This social whale is known for the VERY long tooth that males have. Very little is known about this whale.

All narwhals have two teeth in their upper jaw. After the first year of a male narwhal's life, its left tooth grows outward, spirally. This long, single tooth projects from its upper jaw and can grow to be 7-10 feet (2-3 m) long. Tusks are usually twisted in a counterclockwise direction and have a hollow interior. The tusk's function is uncertain, perhaps used as a formidable jousting weapon in courtship and dominance rivalry, in obtaining food, and/or for channeling and amplifying sonar pulses (which they emit). The tusk is not used in hunting. Long ago, narwhal sightings reinforced (or started) the unicorn legends.